This paper emphasizes the importance of collecting information on corruption, while still stressing critical aspects of the most applied sources of such information, the cross-country composite corruption indices. Are these indices damaging and misleading or are they informative and useful? The paper points to the implication of the lack of a clear distinction between legal and illegal payments or ways of gaining influence. It summarizes the main limitations of Transparency International's Corruption Perceptions Index (CPI), underscores the problem of expecting perceptions to be reliable, and discusses the problem of incorrect understanding and usage of the index. Publicity does not necessarily mean progress, and the construction of the CPI should be influenced by the way this index is applied by the public. A final question is whether it is possible to increase the CPI's value by creating incentives for states to improve their achievements under, for instance, the OECD anti-bribery convention.